That's true "even though you'll be dreading it and want to text," Randall said.

It's a good idea to practice beforehand, she added, so you know exactly what you're going to say and don't get flustered.

Any earlier and you can probably communicate via text or email.

Whether you're communicating over phone, text, or email, Randall said you can keep it simple: "It's not going to work out tonight. I'm so sorry."

You can even soften the blow a little, especially if it's a one-on-one meeting: "Next time coffee's on me!"

If the event is ticketed, offer to pay for the price of your ticket.

Most importantly, Randall said, remember that you don't need an excuse. In fact, she added, "excuses can really get you in a deeper pit" as you try to cover up one white lie with another.

If the person hosting the event asks why you can't make it, you can repeat yourself: "It's just not going to work out. Thank you for thinking of me." Alternatively, you can say, "A personal matter came up" — the person would have to be pretty gutsy to press for more details.

Randall said it's fine if that personal matter is sitting on your couch, drinking wine, and watching Netflix — it's your prerogative what you do with your time.

Keep in mind: It's totally acceptable to back out of an event once in a while. But if you continue weaseling your way out of events at the last minute, you may justifiably earn a reputation for being a flake.